voltha-periodic tests to use voltha-2.1

Change-Id: I667acef4b1b0641e82c96a8b18358e8b60d581ea
diff --git a/jjb/pipeline/voltha-go-tests.groovy b/jjb/pipeline/voltha-go-tests.groovy
index 62b62b7..1dae7cf 100644
--- a/jjb/pipeline/voltha-go-tests.groovy
+++ b/jjb/pipeline/voltha-go-tests.groovy
@@ -40,7 +40,7 @@
       steps {
         sh """
            cd kind-voltha/
-           VOLTHA_LOG_LEVEL=DEBUG TYPE=minimal WITH_RADIUS=y WITH_BBSIM=y INSTALL_ONOS_APPS=y CONFIG_SADIS=y FANCY=0 ./voltha up
+           EXTRA_HELM_FLAGS="--set defaults.image_tag=voltha-2.1" VOLTHA_LOG_LEVEL=DEBUG TYPE=minimal WITH_RADIUS=y WITH_BBSIM=y INSTALL_ONOS_APPS=y CONFIG_SADIS=y FANCY=0 ./voltha up
            """
       }
     }